In the prior art, after the two-staged enthalpy-increasing compressor with two rotors increases enthalpy through replenishing gas, the pressure and the flow velocity of the refrigerant in different sections of the medium-pressure gas passageway are different, whereas the cross sectional areas of different sections of the medium-pressure gas passageway are the same. Consequently, the flow velocity fluctuation between the gas discharge of the low-pressure compression component and the gas suction of the high-pressure compression component is greater, which will affect the discharge plumpness and the suction plumpness of the compressor, and accordingly, will reduce the working efficiency and the energy efficiency ratio of the compressor, and increase the energy consumption.